RTCPeerConnection: datachannel event

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

A datachannel event is sent to an RTCPeerConnection instance when an RTCDataChannel has been added to the connection, as a result of the remote peer calling RTCPeerConnection.createDataChannel().

Note: This event is not dispatched when the local end of the connection creates the channel.

This event is not cancelable and does not bubble.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

js
addEventListener("datachannel", (event) => {});

ondatachannel = (event) => {};

Event type

An RTCDataChannelEvent. Inherits from Event.

Event RTCDataChannelEvent

Event properties

Also inherits properties from Event.

channel Read only

Returns the RTCDataChannel associated with the event.

Examples

This example sets up a function that handles datachannel events by gathering the information needed to communicate with the newly added RTCDataChannel and by adding event handlers for the events that occur on that channel.

js
pc.addEventListener(
  "datachannel",
  (ev) => {
    receiveChannel = ev.channel;
    receiveChannel.onmessage = myHandleMessage;
    receiveChannel.onopen = myHandleOpen;
    receiveChannel.onclose = myHandleClose;
  },
  false,
);

receiveChannel is set to the value of the event's channel property, which specifies the RTCDataChannel object representing the data channel linking the remote peer to the local one.

This same code can also instead use the RTCPeerConnection interface's ondatachannel event handler property, like this:

js
pc.ondatachannel = (ev) => {
  receiveChannel = ev.channel;
  receiveChannel.onmessage = myHandleMessage;
  receiveChannel.onopen = myHandleOpen;
  receiveChannel.onclose = myHandleClose;
};

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-rtcpeerconnection-ondatachannel

Browser compatibility

BCD tables only load in the browser

See also